Introduction. Visual evoked potential (VEP) is an electrophysiological exploration to detect the response to light stimulus and reveal visual pathways. Material and methods. VEP study in patients with diabetes mellitus (DM), assessment of cortical and retinal activity, and identifying the role of this investigation in the diagnosis of diabetic retinopathy. A case-control study conducted to investigate two groups: the first group included 108 patients (216 eyes) with different stages of diabetic retinopathy, and the second group included 108 patients wihout dabetic retinopathy (216 eyes). All subjects have been ophthalmologically and neurologically tested, also using visual evoked potentials. The patients have been exposed to mono-ocular, non-patterned stimuli, using LEDgoggles glasses. Results. A important increase in P100, N75 and N135 wavelength latency in diabetic patients has been observed when compared to control group (p<0.05). In addition, the amplitude of the P100 wave has changed in patients with diabetic retinopathy in comparison to control group. Conclusions. Changes in latency of waves registered on the VEP pathway and the amplitude of the P100 wave have been observed in patients with diabetic retinopathy, which proved the importance of this study in the diagnosis of diabetic retinopathy and the possibility to examine the prognosis of this disabling disease.